Dental engines



' Feb. 5, 1963 A. s. JOHANSSON DENTAL ENGINES Filed June 21, 1957 Fig.

o a m 4 w 2 w v M a M P l I a a 6 7 2 E 6 O 3 4 5 4 4 3 O 2 9 5 w n/v $12 2 4 N. 8 s a E; SE \x\ 4 7 B 5 7 United States Patent Atlas Copco Aktiebolag, Nacka, Sweden, a corporation of Sweden Filed June 21, 1957, Ser. No. Claims priority, application Sweden June 30, 1956 Claims. (CI. 32-23) This invention relates to dental engines comprising a hand piece with means for fitting a dental drillor other implement at the forward end and a pressure fluid operated motor at the rear end of said hand piece. Such dental engines, furthermore, comprise a motor housing, a rotor mounted to rotate in said housing, and an intermediate shaft in the hand piece adapted to be driven by said rotor and providedwith means for receiving said dental drill or the like in driving connection with said shaft. One object of the invention is to provide a dental machine of this type which has small dimensions and which is easily manipulated and which is capable of replacing the conventional cord transmission driven dental machines. A further object of the invention is to provide a pneumatic dental engine in which the pressure fluid is supplied through a connection at the rear end of a motor housing arranged at the rear end of the hand piece thereby producing a better balance of the dental engine and an arrangement in which the hose or the like for supply of pressure fluid to the dental engine is more out of the way of the dentist than in pneumatic dental engines of this type heretofore known. Other features of the invention will be apparent from the following specification and claims and the drawing which illustrates one embodiment of the invention which, however, is not limiting of the scope of the invention as set forth in the claims.

In the drawing FIG. 1 is a longitudinal section of the rear end of the hand piece and of the motor for a dental engine embodying the invention and FIG. 2 is a longitudinal section of the forward end of the hand piece of the dental engine.

The dental engine illustrated in the drawing comprises a motor housing which includes a forward casing 1 and a rear casing 2 which may be bolted or otherwise secured to the forward casing. The rear casing is provided with a threaded projection or boss 3 in which a hose connection 4 is fitted and through which pressure fluid such as compressed air is supplied to the motor housing. In the motor housing a pressure fluid driven rotor 5 is fixed on a shaft 6 which is rotatably mounted in ball bearings 7, 8. The rear casing 2 has a. wall 9 screw threaded on a housing 10 for the ball bearings 7, 8. The wall 9 is provided with a number of openings 11, at the periphery formed as guide passages for the pressure fluid. An annular admission chamber 12 is formed between the wall 9 and the rear casing. The connection 4 and the projection 3 is bored and communicates with the admission chamber 12 through a bore 13. A ball valve 14 loaded by a spring 15 is fitted in the bore in the projection 3 and the connection 4 and controls the supply of pressure fluid to the admission chamber 12.

,A hand piece is fitted in the front casing 1 of the motor housing in conventional manner. Said hand piece comprises a substantially tubular housing 16 which is inserted in the forward casing 1 by being pushed into a bore in the forward motor casing 1 and retained in inserted position by a leaf-spring loaded ball lock 17. The housing 16, which comprises two sleeves mounted one within the other, accommodates an intermediate shaft 18 which is mounted in a ball bearing 19 and a needle roller bearing 20. The intermediate shaft 18 is provided with a coupling member 21'which when the hand piece is inserted in the forward casing 1 engages a coupling member 22 secured ice on the shaft 6. The coupling member 22 forms a braking cone 23 which co-operates with a tapering surface 24 of a brake drum formed by a sleeve 25. The sleeve 25 is screw-threaded in an external sleeve 26 which is axially movable in the forward motor casing 1 against the action of a spring 27. The sleeve 26 has a radial outwardly directed finger 28 which engages a pin 29 by means of which the ball valve 14 may be lifted from its seat. The spring 27 is 'fitted between the sleeve 25 and a spring retainer 30 resting on a spring clip 31 in the forward motor casing 1. The hand piece carries a chuck 32 in the forward end which is adapted to receive the shank of a dental drill or other implement and said chuck may for instance be made in the same way as the chuck 43, 44, 45 illustrated in the assignees co-pending patent application Ser. No. 566,654, filed February 20, 1956, now Patent No. 2,855,671 granted October 14, 1958. The chuck consists of the sleeve 32 which is screw-threaded at 33 in the forward end of a bore 41 in the intermediate shaft 18. The inner end of the sleeve 32 is provided with an internally tapering portion 34. Said portion embraces a tapering portion 35 on a spanner sleeve 36 which is longitudinally split as indicated at 37 and 38 and. which is furthermore provided with a second external tapering portion 39 which fits a corresponding internal tapering surface 40 at the inner end of the bore 41 in the shaft 18. When the sleeve 32 is screwed into the shaft 18 the tapering portions 35 and 39 are pressed together and are consequently pressed to hold the shank of a drill or other implement which has been inserted in the sleeve 36. The sleeve 32 is provided with teeth at the forward end as indicated at 42 and said teeth may engage corresponding teeth 43 inside the forward end 44 of the hand piece when it is desired to turn the sleeve 32 relatively to the shaft 18. In order to make possible screwing down and unscrewing of the sleeve 32 the sleeve 16 is axially movable rearwardly towards the shaft 18 which upon engagement of the teeth 42 and 43 may be turned manually by means of a knob 45 provided on the shaft 6 at the rear end of the rear motor casing 2.

A leaf spring 46 is secured in the housing 16 at 47 and is longitudinally slideable at 51. When the leaf spring is pressed against the housing 16 the inner end of said spring moves the sleeves 25 and 26 against the action of the spring 27. This movement loosens the engagement of the brake cones 23 and 24 and simultaneously opens the main valve 14 so that pressure fluid is supplied to the rotor 5 for driving the same. The shaft 18 is maintained in the illustrated position during operation of the dental engine by springs 48 and 49. The pressure fluid from the rotor 5 is exhausted to the atmosphere through exhaust openings 50.

What I claim is:

1. A dental engine comprising a hand piece with means for fitting a dental drill or other implement at the forward end and a pressure fluid operated motor having a housing at the rear end of said hand piece, a rotor mounted to rotate in said housing, an intermediate shaft in the hand piece adapted to be driven by said rotor and provided with means for receiving said dental drill or the like in driving connection with said shaft, a pressure fluid supply connection on said motor housing at the rear side of the rotor, a passage in said connection and the housing for supplying pressure fluid to said housing for driving the rotor, a main valve in said passage at the rear side of the rotor for controlling the supply of pressure fluid to the rotor, manually operable control means at said hand piece for said main valve, and means extending from the forward side of the rotor to the rear side of the rotor and forming operating transmission means for operably transmitting the motion of said control means at the hand piece to the main valve.

2. A dental engine comprising a hand piece with means for fitting a dental drill or other implement at the forward end and a pressure fluid operated motor having a housing at the rear end of said hand piece, a rotor mounted to rotate in said housing, an intermediate shaft in the hand piece adapted to be driven by said rotor and provided with means for receiving said dental drill or the like in driving connection with said shaft, a pressure fluid supply connection on said motor housing at the rear side of the rotor, a passage in said connection and the housing for supplying pressure fluid to said housing for driving the rotor, a main valve in said passage at the rear side of the rotor for controlling the supply of pressure fluid to the rotor, valve actuating means in the motor housing slideable axially in the motor housing and extending in the motor housing in pressure fluid tight relation with the forward side of the rotor past the rotor to the valve at the rear side of the rotor, and manually operable means carried by said hand piece adapted to move said valve actuating means in the forward portion of the motor housing axially in order to open said valve.

3. A dental engine as defined in claim 2 in which the valve actuating means in the forward portion of the housing extend past the rotor outside the periphery of the rotor.

4. A dental engine as defined in claim 2, in which said valve actuating means comprises a sleeve slidable axially in said hand piece forward of said rotor, a laterally extending projection on said sleeve and a pin axially slidable in said motor housing radially outside of and past said rotor, said pin being located to be engaged by the projection on said sleeve.

5. A dental engine comprising a hand-piece member with means for fitting a dental drill or other implement at the forward end of said member and a pressure fluid operated motor unit removably fitted at the rear end of said member and comprising a housing, a rotor, and anti-friction bearings rotatably mounting said rotor in said housing, means for driving a dental drill or other implements by said rotor including an intermediate shaft mounted in the hand-piece member and in driving association with said drill or implement and separable coupling means providing a driving connection between said rotor and said intermediate shaft, said coupling means being engageable by axial movement of said hand-piece member toward said motor unit to assemble said motor unit with said hand-piece member, passages in said housing for conveying pressure fluid to said rotor for driving said rotor, an exhaust passage in the rear portion of said dental engine for leading pressure fluid away from said rotor, admission valve means in the housing at the rear side of said rotor and control means carried by the dental engine for operating said valve to admit pressure fluid to the motor, to regulate the flow of pressure fluid to the motor and to close the pressure fluid supply to the motor.

References Cited in the file of this patent UNITED STATES PATENTS 2,618,064 Norlen Nov. 18, 1952 2,664,632 Norlen Jan. 5, 1954 2,855,671 Lundgren et a1. Oct. 14, 1958 FOREIGN PATENTS 561,203 Germany Oct. 12, 1932 

1. A DENTAL ENGINE COMPRISING A HAND PIECE WITH MEANS FOR FITTING A DENTAL DRILL OR OTHER IMPLEMENT AT THE FORWARD END AND A PRESSURE FLUID OPERATED MOTOR HAVING A HOUSING AT THE REAR END OF SAID HAND PIECE, A ROTOR MOUNTED TO ROTATE IN SAID HOUSING, AN INTERMEDIATE SHAFT IN THE HAND PIECE ADAPTED TO BE DRIVEN BY SAID ROTOR AND PROVIDED WITH MEANS FOR RECEIVING SAID DENTAL DRILL OR THE LIKE IN DRIVING CONNECTION WITH SAID SHAFT, A PRESSURE FLUID SUPPLY CONNECTION ON SAID MOTOR HOUSING AT THE REAR SIDE OF THE ROTOR, A PASSAGE IN SAID CONNECTION AND THE HOUSING FOR SUPPLYING PRESSURE FLUID TO SAID HOUSING FOR DRIVING THE ROTOR, A MAIN VALVE IN SAID PASSAGE AT THE REAR SIDE OF THE ROTOR FOR CONTROLLING THE SUPPLY OF PRESSURE FLUID TO THE ROTOR, MANUALLY OPERABLE CONTROL MEANS AT SAID HAND PIECE FOR SAID MAIN VALVE, AND MEANS EXTENDING FROM THE FORWARD SIDE OF THE ROTOR TO THE REAR SIDE OF THE ROTOR AND FORMING OPERATING TRANSMISSION MEANS FOR OPERABLY TRANSMITTING THE MOTION OF SAID CONTROL MEANS AT THE HAND PIECE TO THE MAIN VALVE. 